The results bust the myth that anyone - and that includes athletes - can outrun a bad diet.

“The evidence now suggests that up to 40 percent of those within a normal weight (BMI) range will none the less harbour harmful metabolic abnormalities typically associated with obesity,” warned experts in an editorial that appeared in the British Journal of Sports Medicine.

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Few people realise this and many wrongly believe that obesity is entirely due to lack of exercise - a perception that is firmly rooted in corporate marketing.

The prevalence of diabetes increases 11-fold for every 150 additional sugar calories consumed daily, compared with the equivalent amount of calories consumed as fat.

The evidence now suggests that carbs are no better.

Recent research indicates that cutting down on dietary carbohydrate is the single most effective approach for reducing all of the features of the metabolic syndrome and should be the primary strategy for treating diabetes, with benefits occurring even in the absence of weight loss.

Furthermore, research suggests that rather than carbohydrate loading ahead of intense exercise, athletes would be better off adopting a high fat low-carb diet.

The food environment needs to be changed so that people automatically make healthy choices, suggest the authors.

This "will have far greater impact on population health than counselling or education. Healthy choice must become the easy choice", they wrote.

They describe the public relations tactics of the food industry as "chillingly similar to those of Big Tobacco", which deployed denial, doubt, confusion and “bent scientists” to convince the public that smoking was not linked to lung cancer.

“Celebrity endorsements of sugary drinks and the association of junk food and sport must end," they declared, adding that health clubs and gyms need to set an example by removing the sale of these products from their premises.

Public health messaging has unhelpfully focused on maintaining a “healthy weight” through calorie counting but it is the source of the calories that matters.